Lt14mla

iTrader: (2)

Just need a clarification

Backspace on ruff rims 9.5 width

centerline 4.75
offset 45mm
lip width 3"

4.75+0.45+3=8.2 backspace
Does this sound right? Just want to make sure because I'll be looking for a 12 bolt and want everything to line up. Thanks

leadfoot4

iTrader: (1)

Your math is a little off....

Total width of the rim is roughly 10.5", as you include the beads;
Offset of 45mm = 1.77"

So, you take half the rim width, 5.25", add the offset, 1.77" = 7.02"

This gives you an approximate backspacing of 7"

BlackScreaminMachine

iTrader: (17)

a 12 bolt, if its like a Moser will fit stock wheels fine and you can apply the same rules with that rear as you do with a stock GM 10 bolt. IF its an old style 12 bolt from a older GM, then I can see why your doing the math.

ZFSix

iTrader: (14)

leadfoot, you use the advertised rim width not the width from edge to edge, that's not how manufacturers measure them.

9.5" with a 45mm should sit right at the edge of your fenders.

9.5/2 = 4.75 + 45mm (1.77") = 6.52" backspace.

leadfoot4

iTrader: (1)

Not always.....If you don't include the additional width incurred with the beads, you might not have enough clearance on a "tight" application, and this is why some manufacturers include it.

Lt14mla

iTrader: (2)

hmmm.. i read something about including the lip width? no? Tyring to figure out what length 12bolt i need. Ive seen a few but some were shortned